Insecticidal composition



Patented Jan. 24, 1939 msrc'ncmar. com'osmon William B. Parker,Placer-ville, Oalit., assignor to Californla'Spray-Chemlcal Corporation,Berkeley, Calif., a corporation of Delaware No Drawing.

Application August 27, 1934,

Serial No. 741,721

16 Claims.

This invention relates to a new insecticidal oil composition and moreparticularly to a new form in which it has been found highlyadvantageous to apply the known insecticidal mineral oils to parasiteinfested vegetation.

The insecticidal value of various distillates from petroleum and coaltar oils has long been recognized and many methods have hitherto beenproposed for utilizing this inherent value. Oils 9 generally have beenapplied in one or other of two forms, either as such and substantiallyundiluted or as dilute emulsions of oll-in-water.

The surfaces of both the insects and the plant tissues which they infestare usually more readily 5 wet by oil than by water so that the obviousmethod of securing a complete coverage of the host surfaces andeffective contact with the insect was to apply the oil as such. This ishowever usually undesirable in at least two major respects.

The amount of oil theoretically necessary to produce an, adequatecoverage is very small and, so far as I am aware, but a single entirelypractical means, copending application Serial No. 635,861,

of distributing such a small bulk of material uniformly over a largearea extended in three dimensions has yet been devised. When a bulk ofoil which could be uniformly distributed by ordinary spray methods oversuch an area has been employed it has been both uneconomical and o inmost cases decidedly detrimental to the vegetation treated.

In order to escape these diiiiculties recourse was had to the use ofdilute emulsions of oil-in-water in which the oil constituted from about1 to 5 percent of the total volume. Thus a bulk of material sufficientto permit of uniform distribution was provided but by a means which wascompletely illogical in at least one other essential respect. Apparentlythe only reason that it has endured as long as it has and has receivedthe wide adoption that it has is because there appeared no otherpossible way of economically realizing even a part of the insecticidalvalue of mineral oils.

The shortcomings of an oil-in-water emulsion insecticide are now so wellknown as to need scarcely more than mention. Such emulsions having anaqueous continuous phase are of necessity water wetting and thus insteadof contributing to the insecticidal power of the oil actually protecttheinsects from the oil by first drenching them with a layer of water sothat the dispersed oil droplets easily run ofi and are either lost inthe drip from the leaves or when retained at all do not give a complete,insect impervious,

covering. While a slight increase in economy and utility has beenrealized through decreasing the stability of the emulsions until theyapproach the point of being no longer applicable due to breaking andstratification during the process of 5 application the undesirablefeatures inherent in an aqueous continuous phase have not beeneliminated or even substantially mitigated.

It is the main object of this invention to provide a form in whichmineral oils may be applied as insecticides with the substantial.elimination of the foregoing disadvantages which attend the applicationof oil in either of the two previously used forms.

It is a further object of my invention to provide means whereby oil maybe rendered in a form which is economical and practical as aninsecticide and easily possible of application by known methods.

Broadly I have discovered that oil in a third, and, so far as I amaware, new form, as far as insecticidal work is concerned, is realizedin a water-in-oil emulsion. Such an emulsion, in which the continuousphase is oil, is of necessity oil wetting and is thus the complete equalin this 26 desirable characteristic of undiluted oil. The extent towhich water may be dispersed in oil and hence the extent to which oilmay thereby be increased in bulk for ease of uniform distribution islimited only by the efliclency of the water- 80 in-oil producingemulsifiers which are available.

Water-in-oil emulsions'have not heretofore received considerableapplication in any branch of industry and consequently but little isknown concerning their prepartion and properties and that little is of apurely theoretical or academic nature. I have found, however, that evenwith the limited knowledgev and range of materials available perfectlyuniform and stable dispersions of water in oil may be preparedcontaining or more water. The increase in bulk thus efiected is entirelyadequate to make even the minimum theoretically necessary quantities ofoil applicable without difiiculty and without resort to the doublyobjectionable increase in oil formerly required. 5

I have found that the polyvalent metal soaps of the ordinary fatty acidssuch as oleic, stearic, palmitic, etc., are effective in producingstable water-in-oil emulsions when water is introduced into an oilsolution of about 1 to 5% of the B0 emulsifier just" as oil isintroduced into the aqueous phase in the preparation of conventionaloil-in-water emulsions.

As disclosed in my copendlng application Serial No. 741,722, certain ofthese same soaps dissolved ll in oil are highly effective inpreventingthe oil from being absorbed by growing vegetation and thus make possiblethe remarkably complete elimination of the customary oil damage tofoliage and fruit. When these same jell-forming soaps are employed aswater-in-oil emulsifiers in the present invention they may thus servethe double purpose of also rendering the oil relatively non-absorbableby living plant tissues.

It has been found that in general the amount of such a soap which isnecessary to render a given oil incipiently jail-forming will be morethan enough to give any desired amount of water dispersion in the sameoil. It may however some- 1 times be necessary to use slightly more soapto eifect both results in the same composition.

The physical form which is taken by a water dispersion in such ajell-forming oil composition when atomized and applied by the process ofmy copending application Serial No. 635,861 or an equivalent method isso far as both the host plant and the insects are concerned, identicalwith that which is formed by the jell-forming oil alone. That is, auniform coating of fine, dis crete, more or less spherical oiljelly-balls so close together as to constitute complete coverage frominsects but so far apart as to permit of free respiration by the planttissue is deposited. The only difierence is that the center one-half tofour-fifths of each jelly ball is water and not oil. Assuming the samesize and number of particles per unit of surface an identical coveragecan thus be effected with an expenditure of but one-half to one-fifththe amount of oil.

Experiments conducted on a full commercial scale have demonstrated theentire practicability and desirability of this new type insecticide. Itpossesses a combination of safety to plants. efficiency in oilutilization, low overall cost, ease of preparation and eificacy in highpercentage insect kill not approached by any other sort of mineral oilinsecticide preparation of which I am aware.

The large number of possible variations and extensions of the basicprinciple of this invention will be readily apparent to one skilled inthe art. Oil soluble toxic materials such as rotenone and pyrethrummaybe added to the oil phase, water soluble toxic materials such asnicotine and other alkaloid salts, lime sulfur, etc., may be included inthe water, water insoluble but suspendable materials such as leadarsenate, Bordeaux mixture or the newer copper silicate gel fungicidesmay be suspended in either the aqueous or oil phase, or soaps of thefungicidally active metals such as copper,- lead, mercury or zinc may beincorporated in the oil. In general it will be found possible toconstruct combination parasiticides with my water-in-oil emulsions justas has in the past been possible with the oil-in-water type ofemulsions. regard being had of course to the inherently differentproperties of the reverse type emulsions.

The range of insecticidal oils which may be employed in mywater-in-jell-forming oil emulsions is the same as in the jell-formingoils alone and includes not only the usually accepted oils but also morevolatile oils due to the reduction in vapor pressure occasioned by thejell and also less highly refined oils due to the substantialelimination of oil absoiption by the vegetation likewise brought aboutby the jelling action.

One improvement on the simple water-in-oil emulsions as such has beenfound to consist in the addition of thickening or bodying agents to theaqueous phase. core of the oil droplets deposited to help in sup- Thispermits the aqueous porting and maintaining the droplets as such andwhen an insoluble agent is suspended in the aqueous phase the bodyingagent will prevent its being prematurely squeezed out with consequentdisruption of a considerable part of 1 the emulsion. Such highlyhydrophyllic colloids what I claim is:

1. An insecticide comprising a mineral oil continuous phase having anaqueous phase dispersed therein.

2. An insecticidal composition comprising a mineral oil continuousphase, an emulsifier adapted to the formation of a water-in-oil type ofemulsion and an aqueous phase dispersed in said oil.

3. An insecticidal composition comprising a mineral oil continuousphase, a polyvalent metal soap and a dispersed aqueous phase.

4. An insecticidal composition as in claim 3 wherein the polyvalcntmetal soap is incorporated in the continuous oil phase and is of thetype which tends to render said oil phase jell-forming.

5. An insecticidal composition as in. claim 3 wherein the polyvalentmetal soap is aluminum stearate.

6. An insecticidal composition consisting of a mineral oil continuousphase having a polyvalent metal soap incorporated therein in an amountresulting in incipient jell-formation and having an aqueous phasedispersed therein.

7. An insecticidal composition as in claim 6 in which the polyvaientmetal soap is aluminum stearate.

8. An insecticidal oil emulsion composition in which a refined mineraloil constitutes the continuous phase and an aqueous liquid thediscontinuous phase, the volume ratio of oil to aqueous phase being atleast one to four.

9. An insecticidal oil emulsion composition comprising a refined mineraloil as the continuous phase, an emulsifier adapted to the formation of awater-in-oil type of emulsion and an aqueous discontinuous phasedispersed in the oil, the volume ratio of oil to aqueous phase being atleast about one to four and the dispersion being sufficiently stable topersist as such until deposited on a parasite infested host.

10. An insecticidal oil emulsion composition as in claim 9 wherein theemulsifier is a polyvalent metal soap.

11. An insecticidal oil emulsion composition as in claim 9 wherein theemulsifier is a polyvalent metal soap dissolved in the oil in quantityto produce incipient jel formation.

12. An insecticidal oil emulsion composition as in claim 9 wherein theemulsifier is aluminum stearate dissolved in the oil in such quantity asto produce incipient jelling of the oil.

13. An insecticidal oil emulsion composition as in claim 9 wherein theemulsifier is aluminum stearate dissolved in the oil in quantity toproduce incipient jelling of the same and the aqueous phase contains athickening agent.

14. An insecticidal spray comprising a mineral oil external phase havingan aqueous phase enclosed therein.

15. The method of increasing the bulk of a mineral oil insecticide formore effective spraying and at the same time of retarding the absorptionof said oil when applied to vegetation which comprises dispersing anaqueous phase in said oil with the aid of a polyvalent metal soapemulsifier of a type which tends to produce Jeliing of the 16. Themethod of increasing the bulk 01. a mineral oil insecticide for moreeffective spraying and at the same time of retarding the absorption ofsaid oil when applied to vegetation which comprises dispersing anaqueous phase containing a thickening agent in said.- oil with the aidof a polyvalent metal soap emulsifier of a type which tends to producejeiiing of the oil.

WILLIAM B. PARKER. 10

